It seems like muscle tone is a factor when you're choosing a cup? I'm under the impression that women with poor muscle tone do better with a stiff cup, right? Does the opposite hold true? That women with great muscle tone should use a soft cup? I don't know... I've read that women with great muscle tone can "crush" soft cups? Ugh, I feel confused. My own muscle tone is average-ish (slightly on the poor side, not very far from average though) and I wanna know what's up. I currently have the Si-bell cup which is very soft, will I need a stiffer cup or will it likely be fine if I improve my muscle tone?

I'm pretty sure it's the opposite of what you said first.. If you have strong muscle tone, you need a stuffer cup (hence the stiff MeLuna cups called "sport") I had been using a soft MeLuna with great success (I was pretty sedentary with poor muscle tone) until I started doing a ton of core work and running. I started leaking like crazy whenever I would roll over in bed or go from sitting to standing or vice versa. I got another cup of the same size but with medium stiffness and now I'm not leaking at all (even on heavy days)! I'm just hoping I don't need to buy yet another cup when I eventually get ripped (which I fully intend to do :p)

I had a large MeLuna soft and once I started doing major core work and running I switched to a large MeLuna classic. I think you should be fine with the si-bell as long as your not going to do ridiculous amounts of core work - but even then it may still suit you fine, you just never know until you try

I have a si-bell and I'm pretty sure average muscle tone and it's awesome for me, never leaks, opens easily and doesn't press on my bladder like nearly every other cup I've tried! Tried the meluna classic and meluna sport prior to that and didn't find much difference between the two tbh, could feel the both nearly all of the time and did suffer leaks.

My core muscles should be in pretty decent shape (I dance, hike, and swim), and don't have a problem with my large Cuplee, which should be almost as soft as your Si-Bell. The Meluna mini small soft leaks a bit for me, though. I think TPE is a bit less springy than silicone and doesn't hold its shape as well. At a guess, your Si-Bell will be fine.

I think it really depends. I'm 18 and sexually active, small build (5'4" and 115 pounds) and I find myself doing Kegels constantly without realizing it, so my muscle tone down there is A+. When I started using Meluna soft, the damn thing would leak incessantly because my muscles would crush the cup and break the seal- but using a firmer cup would likely be painful for me, as I'm quite petite down there and can usually feel tampons. I've found the solution! I insert the cup using the punchdown fold, and pop it open as soon as the rim is fully inside (with the rest of the cup sticking out). Then I make sure the cup is perfectly round and open, and I push/kegel it up and into position. Hope this helps! Softer cups are totally feasible for strong pelvic muscles if your cervix is high enough to allow the cup to sit just above the PC muscles.